Fuel for running vehicle engines is contained in one or more fuel tanks appropriately mounted on the vehicle. Fuel is admitted to a fuel tank through what is referred to herein as a filler tube. The filler tube extends into the interior of the fuel tank. In order to fill the fuel tank, one must remove the fuel cap from the filler tube to expose an open upper end. The filler tube is closed by the fuel cap at times other than when fuel is being admitted to the fuel tank.
The fuel cap is used to cover the open upper end of the filler tube and also prevents the flow of fuel back out the tank when a car is in an accident, for example, in a rollover accident. The cap also helps to reduce the chances of fuel leaks and their associated dangers and substantially prevents the leakage of fuel vapors from the filler tube, which can be a major source of hydrocarbon emissions.
A fuel cap typically consists of a plastic body with either threads (older caps) or lugs that are received onto the open upper end of the filler tube of the vehicle fuel tank. Caps may be available in standard or locking types. Unfortunately, even locking fuel caps may be breached or compromised permitting fuel theft by siphoning or the like and vandalism. The theft of gas has become of great concern with the rising cost of fuel. In addition, vandals may introduce contaminants or destructive additives such as sugar or water into the fuel.
Accordingly, there has been a need for a novel improved fuel cap and filler tube assembly which is of simplified construction, inexpensive to manufacture, and substantially effective at preventing tampering or theft of the fuel in the fuel tank. The present invention fulfills these needs and provides other related advantages.